Enhancement of molecular weight build up in polyimides using ether solvents

Two linear polyimides were prepared in various ether and amide solvents. The inherent viscosity was then monitored as a function of time. The polymers made in the ether solvents consistently gave higher inherent viscosities, and thus molecular weights, than the same polymers made in the amide solvents. This molecular weight buildup is attributed to the unique solvation mechanism of the ether solvents which enhances the basicity of the amines via hydrogen bonding.